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United States ate
ice
3,077,929
Patented Feb. 19, 1%63
1
2
method for removing paraffin depositions from metal sur
349773295
USE OF QUATERNARY
ONIUM SALT§
FGR PARAFFEN REMOVAL
Michael J. Fetkovich, Bartlesville, Okla, and Norman L.
sargent, Dumas, Tex, assignors to Phillips Petroleum
Company, a corporation of Delaware
No Drawing. Filed Dec. 14, 1959, Ser. No. 859,116
10 Claims. (Cl. 166—41)
'
This invention relates to the use of quaternary ammo 110
nium salts for para?in removal from metal surfaces in
contact with para?in-rich hydrocarbons. In another
aspect it relates to the continuous removal of para?in
from the tubing in a producing well by carrying it to the
surface in the moving hydrocarbon ?uid. In still another 15
aspect it relates to removing accumulated paraliins in
solid chunks from gas and oil well tubing and casing
strings by periodic treatment with the composition of this
invention.
in oil production, because of the high para?in content 20
of some crude oils, certain types of producing wells soon
become plagued with impeded flow rates, even though
faces w‘n-ich are in contact with hydrocarbon ?uids during
the production and transportation of such ?uids.
Various otherlobjects, and advantages and features of
the invention will become apparent from the following
description and appended claims.
7
In accordance with the present invent-ion, oil-soluble
solutions of quaternary ammonium, salts in a suitable or;
ganic solvent are prepared for the well-treatment.
Speci?c examples of alkyl quaternary ammonium salts
useful in said invention are “Arquads” made by Armour
Industrial Chemical Company, which are alkyl and di
a-lkyl quaternary ammonium halide salts. These
“Arquads'” having the general ‘formulas, for the chloride
salt, as follows:
.
Alkyl trimethylamoniun
Dialkyl dimethylamonium
0 111 ends
chloride
Of these alkyl quaternary ammonium chloride salts,
those having from 5 to 20 carbon atoms in the alkyl
group, or in each alkyl group, as the case may be, are
still be substantial. This results from the deposition of
para?ins on the metal surfaces of the well tubing, steadily 25 especially effective in this invention. The term “alkyl
quaternary ammonium halide salt” as used in this speci?
narrowing the ?ow path for the oil, which will eventually
cation covers both alkyl and dialkyl salts and mixtures of
be closed off entirely.
the same, as many “Arquads” are mixtures. The alkyl
This has necessitated the removal of para?in deposits
radical may be paraffinic, ole?nic, diole?nic, acetylinic,
by cumbersome mechanical devices or by the inhibition
of wax buildup with chemical solvents. In the latter 30 or otherwise unsaturated.
For example, octyl- trimethylammonium chloride, di
method, the concentration of the solvent in the purging
octyl dimethylammonium chloride, decyl trimethylamrno
?uid must be su?iciently high so as to achieve its para?in
the natural ?uid energy of the gas or oil in formation may
dissolving function.
This necessitates the use of com
paratively large volumes of solvent to clean out several
hundred, or perhaps thousand, feet of piping--a rather 35
expensive operation, and one in which the results also
have not been entirely satisfactory.
nium chloride, didecyl dimcthylammonium chloride, do
decyl trimetihylammonium chloride, didodecyl dimethyl
ammonium chloride, tetradecyl trimethylamm-onium chlo
ride, ditetradecyl dimethylammonium chloride, hexadecyl
trimethylammonium chloride, dihexadecyl dimethyl
ammonium chloride, octadecyl trimethylamrnonium chlo
I have discovered that in a periodic lubrication treat
ride, dioctadecyl dimethylammonium chloride, octa
ment, by employing a modest quantity of a commercially
available quaternary ammonium salt in a suitable solvent, 40 decenyl trimethylammonium chloride, dioctadecenyl di
methylarnmonium chloride, octadecadienyl trimethyl
the para?in deposition on well tubing, which has built up
ammonium
chloride, dioctadecadienyl dimethylammoni
enough over a period of time to completely plug the tub
ing, can be ‘overcome in a treatment ranging from about
24 to 240 hours. Alternatively, if it is preferred to avoid
the periodic shutdowns due to plugging followed by the
batch treatment described above, continuous injection of
the additive dispersed in a mineral oil may be practiced.
In this latter method, the para?in would be removed as
it is formed, permitting uninterrupted production from the
um chloride, and mixtures of the same, are all useful in
this invention.
Other alcohol-soluble salts of these alkyl quaternary
ammonium radicals having 5-20 carbon atoms in each
alkyl' group, such' as the other halides, acetates, salts of
other lower carboxylic acids having from 1 to 6 carbon
atoms, sulphates, nitrates and phosphates are effective in
place of the chlorides, but the chlorides are preferred
producing well, as long as this is desired or possible under 50
because they are salts of a stronger acid and a strong base,
proration allowances. The methods of this invention are
which makes them ionize better.
appreciably more economical than the present practice of
Examples of these salts which are all useful in the
continuous injection of necessarily large quantities of
practice of this invention are octyl trimethylammonium
chemical solvents to inhibit the deposition of wax on the
bromide, dioctyl 'dimothylammonium iodide, decyl tri
walls of the well tubing.
methylamm-onium acetate, didecyl dimethylarnmoniurn
It is an object of this invention to provide a composi
propionate, dodecyl trimetlhylammonium' butyrate, dido
tion, and method of using the same, which inhibits wax
decyl dimethylammonium bromide, tetraidecyl <trimethyl~
deposition from para?in-rich crude oil.
Another object is to provide a method for substantially
preventing the deposition of para?lns from crude oils rich 60
ammonium iodide, ditetradecyl dimethylammoniurn ace
tate, hexadecyl trimethyl ammonium butyrate, dihexa~
decyl dimethylammonium phosphate, octadecyl trimethyl~
in para?in on metal surfaces in producing wells.
. ammonium sulfate, dioctyldecyl dimethylammonium 11i
A further object is to provide a composition and meth
trate, and octadecenyl trimethylammom'urn phosphate.
od for removing already formed waxy depositions as solid
TabloI provides a tabulation of a number of “Arquadsf’
chunks which are carried to the surface by the hydro 65 marketed by the Armour Company and indicates the
carbon ?uid moving in well conduits.
varied mixtures of alkyl and dialkyl‘groups useful in this
A stillfuither object is to provide a more economical
invention. .
3,077,929
TABLE I
_
Dialkyl Quater-
Alkyl Quaternary Ammonium Ohlondes
Mixed Monoalkyl
nary Ammonium and Dialkyl Quater
Ohlorides
nary Ammonium
Chlorides
“R” Groups
Carbon
Chm-n Arquad
Length
12—33
Arquad
Arquad
Arquad
Arquad
Arquad
Arquad
Arquad
Arquad
12-50
0
s
T
20-50
2045
T-2O
5-20
_
No.01 (Approx).--
n-
_.
_;
Format Room Temp..'_. .-._.,_,.__.
10
41
>
'
t
4
5
23
23
10
17
13
24
4
9
9
10
18
22
50
1
Isopropanol (Approx)--- ....
Water (Approx.) ...... _.l.--
4
5
_
34
_ 15.5 I
Liquid , Liquid
.
36
‘13.5
36
_13._5
Liquid
36
‘13.6
,Lxquld
;v
Liquid
:
'
42
7.5
.
17
7.5
Semi
Semi-
Liquid
Liquid
50
0.5
0.5
36
13.5
36
_13._5
Liquid
Liquid
NorE.—-Arquads 'l‘-2_O and S-2C are mixtures. All the others are either alkyl or dialkyl quaternary ammonium chlorides.
with eight gallons, of water. This load was followed with
produced gas introduced at pipeline pressure for a period
and about 28 percent water is called “Arquad T—2C—50” 25 of about eight minutes, while the annulus was opened to
the pit. At 2:50 p.m., the well was shut in, i.e., all valves
and was used in the examples described later in this ap
plication.
'
'
were. closed,_until the well pressure exceeded the pipeline
pressure. vBeginning at 2:55 p.m., the annulus was opened
Isopropanol is the preferred alcoholic solvent with the
to the pipeline overnight, in order to agitate the ?uids.
alkyl or 'dialkyl quaternary ammonium salts, but other
aliphatic alcohols having from‘ 1 to 8 carbonratoms are 30 At 10:40 a.m., the next morning, a spot reading was
taken. The ?ow rate (Q) was now 92,000 cubic feet
useful in this invention. ‘Methanol, ethanol, l-butanol,
A mixture of 1 part “Arquad T-ZQ" to 1 parthydro
carbon solvent comprising about 72 percent isopropanol
2-methyl-l-propanol, 2-butanol, and 2-methyl-2-propanol
per» day and the Pc2-Pt2=27.*l2. At 10:48 a.m., the well
was shut in and the tubing was opened to the pit. Byv
11:00 a.m., the tubing began‘unloading a few chunks of
preferred after isopropanol, because they arermore polar
than thevother alcohols, and the alkyl'and dialkylquater 35 heavy wax. At, 11:08 a.m., the tubing was apparently
dead, while the shut-in pressure of the annulus was 181.7
nary ammonium halides, acetates, sulfates, nitrates, phos~
p.s.i.g. At 11': 10 a.m., the tubing began unloading more
phates, and salts of lower carbox-ylic acids'having from 1
heavy wax in chunks, the wax being well saturated with
to 6 carbon atoms, that are useful in theinvention are
foam, At 11:18. a.m., the tubingwas still breathing, and
more soluble therein.
'
' The lubricating treatment of this invention can .be done 40 about 1/a gallon of sponge-like wax had. accumulated on
the ground. At 11:31 a.m., it was still unloading more
by means of continuous injection, or on a periodic basis.
heavy slubs of wax. At 11:53 a.m., tubing began unload‘
However, the existence of a packer in the annulus pre
ing more wax- nowmixed with some water. At 12:07
cludes the use of the continuous injection, method. As
p.m., tubing was again apparently dead, and about 7
suming the absence of a, packer, and‘ if. the Well is pro
are all useful in this, invention,‘ methanol being the'next
ducing through the tubing, continuous injection, of the
prepared solution will be through the annulus. Alterna~
tively, if the well is producing through the annulus, the
salt solution may be injected through the tubing. In con‘
gallons; of wax on ground had- been collected up to this
At 12: 10 p.m., slugging from the tubing of a dry
45 point.
brown wax mixed with foam began. At 12:17 p.m., the
tubing. began blowing dry gas mixed with occasional
tinuousinjection, by the use of ajchemical pump, solu
tion may be injected into thev tubing or through the an
nulus, as the case may be, at a rate ranging from 17 pint
up to 1 gallon per day. To achieve the lower ?ow rates
with the same pump, the prepared solution‘ may be fur
ther diluted with water or alcohol.
‘In the case of a well, the production of which is being
prorated, a batch treatment may be preferred, This
treatment may be carried on during the period when the
well is not producing, and‘ a signi?cantly. less amount of
the prepared solution‘ should be requiredthan' if, the treat
ment is performed only after plugging of the well tubing.
An exampleof the application: of the method of_ this in
vention follows:
’
'
Example I
chunks of wax.
Atl2219' p.m., the annulus pressure was
up four pounds-to 185.4 p.s.i.g.
At 1:30v p.m., the tubing was blowing gas while still
unloading some water and a few more slugs of Wax.
By
1235 p.m., the annulus‘ pressure had risen to 189.4 p.s.i.g.
At 1:40 pm.‘ the well‘ was shut-in to run a steel line
measurement. The S.L.M. weight started hitting para?in
at 1520 feet, at 1648 feet, at 1674 feet, at 1682 feet, at
1693 feet, and at'1'694 feet. The tool could not be gotten
below this latter point. At 2:29 p.m., the tubing was
opened straight upto the atmosphere. In ?ve minutes, it
60
’
began. unloading mist and “gunk,” with a good amount of
water.
By 2:50 p.m., the annulus pressure had-risen to
190.9 p.s.i.g., while the tubing was unloading a tan colored
foamy water. By 2:55 p.m., a total of 8 gallons of heavy
wax had been unloaded. A liquid measurement was run
hours, 4 times a day, but little or no liquid was being 65 for about 5‘ minutes on the tubing yielding about 2.3
quarts, or a daily rate of 4 barrels. Gas flow from the
lifted through. the tubing. The ?ow. rate (Q) was
The intermitter on a gas Well was set to blow for 21/2,
79,000 cubic feet per day (M c.f.d.) of gas while the
Pea-Pt =28.27>when a “spot” wasltaken, with thetubing
tubing was 100 thousand cubicfeet per day, by pitot tube
reading. Several days later another steel line measure-v
ment was run. The tool now reached the bottom of they
A steel line measurement was run down the tubing. 70 tubing without further treatment.
vented to the atmosphere.
The line tool hit para?in deposition at 244feet, at 477 feet,
and at 543 feet. The tool dropped very slowly to 721 feet,
but could'not be loweredbelow this point.
At 2:40 p.m., ten gallons of Arquad T-2C'-5‘0 was lu-:v
bricated into the tubing. This was immediately followed
From previous steel line measurements in other wells
of this ?eld, it has been found that the worst para?in de
posits-form from about 800 feet to about» 2,000 feet. As
can be seen from the run described above, several hun.-
dred feet of para?in was removedfrom the tubing.
8,077,929
5
6
Example II
The tubing in a gas well was opened to the pit (vented
to the atmosphere), but no gas was producing.
The well
usually produced through the annulus, but the periodic
production of oil and salt water through the tubing had
permitted enough paraf?n deposition therein, which had
completely blocked off the tubing. The column of liquid
rate of 212 M c.f.d. The well was shut-in overnight.
The following day, the shut-in pressure on the annulus
was 302.5 p.s.i.g. When the tubing was turned into the
pipeline, it died immediately. Upon opening the tubing
to the pit, it kicked off. Regular production of gas was
started through the annulus, and a pinched tubing gate
permitted production of crude oil and salt water there
through.
trapped in the well created a hydrostatic head at the bot
Pc, as used in the above examples, means the shut-in
tom of the well which interfered with the production of
gas through the annulus. A “spot” measurement was 10 pressure of the annulus or tubing, whichever is the higher.
Pt stands for the ?owing pressure in the annulus. The
taken and a flow rate (Q) of 53,600 cubic feet per day
expression POL-Pt2 is accepted in the art as a measure of
(M c.f.d.) was recorded. The Pei-Pt2 equals 49.42.
the operating efliciency of the well. For any given flow
rate, the lower the value of the Pcz-Ptz, the more e?icient
with ?ve gallons of methanol, was lubricated into the one
inch tubing. This was immediately followed with 10 15 the operation of the well.
0n the ?rst day, live gallons of Arquad T-ZC-SO, mixed
gallons of water.
The tubing was next pressured with
While some bene?cial results are obtained with smaller
amounts and in shorter times of treatment, markedly
superior results are obtained in the practice of this inven
was then shut-in and the well was allowed to produce
tion when the treating solution of quaternary ammonium
through the annulus.
On the third day, another spot was taken. Q=35 M 20 salts in alcoholic solvent is injected in amounts of 1 to 20
gallons, the best results being with 5 to 15 gallons, per
c.f.d., and Pc2-Pt2=49.78. At 12:40 p.m., the tubing
well, of from a 2 percent solution to a saturated solution
was repressured with pipeline gas up to 213 p.s.i.g. At
of said salts, said alcoholic solvent containing less than 50
1:80 pm, the tubing was vented to the atmosphere.
percent water, the best results being obtained with over
Though the annulus pressure was 221 p.s.i.g., the tubing
5 percent solutions of said salts, later injecting from zero
gas ?ow was too small to measure. At 1:45 pm, the
to 20 volumes of water per volume of said injected treat
tubing was shut-in and repressured with pipeline gas.
ing solution, better results being obtained with 0.5 to 2
At 2:00 p.m., the tubing was again opened to the atmos
volumes of water per volume of said treating solution,
phere. At 2:45 p.rn., the annulus pressure was up to
later injecting natural gas into said tubing at a pressure
225 p.s.i.g. At 3:00 pm, nothing was coming through
the tubing. The tubing was shut-in and the gas flow from 30 from a little below pipeline pressure to any pressure avail
able while venting well annulus for a period of preferably
the annulus was turned into the pipeline.
1 to 60 minutes, more preferably from 5 to 15 minutes,
On the fourth day, a steel line measurement was run
and shutting in said well preferably from 1 hour to 7 days,
down the tubing to a total depth of 3,188 feet. Paraffin
more preferably from 10 to 30 hours, before venting said
slowed the tool at 1380 feet, at 1790 feet, and again at
1900 to 2260 feet. The annulus was opened to the pit 35 tubing to the atmosphere.
By natural gas it is intended to cover all conate gas
(vented to the atmosphere). The annulus “kicked off”
produced from underground strata in which the major
in 7 minutes, producing a milky looking water and paraf
component is methane, but containing from zero to small
?n. It was shut~in after an hour and 45 minutes. The
amounts of N2, CO2, CO, H28, and C2 to C10, or even
annulus was again suddenly opened to the atmosphere.
higher, carbon chain hydrocarbons in a vapor state in
lt was repressured with pipeline gas and then the tubing
said methane (depending on the pressure and retrograde
was left open to the pin overnight. On the next day, the
vaporization of said higher hydrocarbons in said gaseous
tubing would not “kick off.” Gas producing through the
mixture).
annulus was then turned into the pipeline while the tubing
Various modi?cations of this invention will become
remained open.
apparent to those skilled in the art without departing
Four days later, a “spot” was taken giving a Q up to
from the scope and spirit of the invention, and it should
62 M c.f.d. and the Pcz-Ptz was down to 29.13. The
be understood that the latter is not necessarily limited
tubing gas ?ow rate was still too small to measure. The
to the aforementioned discussion and speci?cation.
tubing was shut-in and the slightly increased gas flow
We claim:
tlnough the annulus was directed to the pipeline.
pipeline gas for a period of several minutes. The tubing
A week later, a second treatment was begun, at which
time a “spot” gave a Q=55 M c.f.d. and a Pc2-Pt2=42.93.
Again 5 gallons of Arquad T—2C—5t'), mixed with 5 gallons
of methanol, followed with 1% gallons of water were intro
duced into the tubing. This load was again followed with
produced gas introduced at pipeline pressure for a period
of several minutes. The tubing was shut~in over the
weekend. On the third day following the second treat~
ment, at 11:11
the annulus was opened to the pit.
1. A method of removing deposits of normally solid
parafrlns from metal surfaces in contact with a hydro—
carbon fluid which comprises the steps of injecting be
tween 1 and 26 gallons of a solution of quaternary am
monium salts selected from the group consisting of mono
alkyl quaternary ammonium salts, dialkyl quaternary
ammonium salts, and mixed monoalkyl and dialkyl qua
ternary ammonium salts, having from 5 to 20 carbon
atoms in each alkyl group in an alcoholic solvent into a
At 11:16 am, it “kicked off” and made foam and salt 60 well tubing plugged by para?in deposits, injecting a
volume of water into said tubing, following the load in
water to the pit. At 11:40 am, it was shut-in and re
said tubing with a stream of natural gas from at least
pressured with pipeline gas at 216 p.s.i.g. At 11:45 a.m.,
about
pipeline pressure for a period of 1 to 60‘ minutes
the annulus was again opened to the pit. At 11:51 am,
while the annulus is vented to the atmosphere, shutting
it “kicked off” and made a milky~looking water to the pit.
At 1:00 pm, the annulus was again pressured with pipe
line gas up to 210 pounds, then the pipeline gas pressure
was alternated back and forth between the tubing and
the annulus.
At 1:30 p.rn., the tubing kicked 011”.
By
1:45 pm, the shut-in pressure on the annulus was up
to 280 p.s.i.g. The tubing started producing liquid.
Four days later, the well head pressure was 220 pounds.
ubing was “making” liquid to the pit. The flow rate was
measured at 222 M c.f.d. The next day, another “spot”
was, taken with a Q==35 M c.f.d. and a Pc2-Pt2=4‘9.78.
Tubing was still “making” liquid to the pit with a flow
the well in until the well pressure exceeds the pipeline
pressure, flowing gas from said well for a period of from
1 hour to 7 days to agitate the injected fluids, and venting
said tubing to the atmosphere, thereby permitting sporadic
discharge of chunks of para?in from said tubing by the
?uid energy of said hydrocarbon ?uid which continues
until unimpeded flow of said hydrocarbon fluid is restored.
2. A method of removing deposits of normally solid
paraf?ns from metal surfaces in contact with a hydro
carbon fluid which comprises the steps of injecting be
tween 1 and 20 gallons of a solution of quaternary am
monium salts selected from the group consisting. of
3,077,929
7
3.
atoms in each alkyl group in an alcoholic solvent into a
a conduit wherein said ?uid contains paraffin constituents
which tend to deposit and build up on the surfaces of said
conduit in contact with said ?uid, the improvement which
comprises injecting into said ?uid a solution of an alco
well tubing plugged by parai?n deposits, injecting a
hol soluble quaternary ammonium salts selected from the
monoalkyl quaternary ammonium salts, dialkyl quater~
nary ammonium salts, and mixed monoalkyl and dialkyl
quaternary ammonium salts, having from 5 to 20 carbon
volume of water into said tubing, following the load in
said tubing with a stream of natural gas at at least about
group consisting of monoalkyl quaternary ammonium
salts, dialkyl quaternary ammonium salts, and mixed
monoalkyl and dialkyl quaternary ammonium salts, hav
pipeline pressure for a period of 1 to 60 minutes while
ing from 5 to 20 carbon atoms in each alkyl group in an
the annulus is vented to the atmosphere, shutting the well
in until the well pressure exceeds the pipeline pressure, 10 alcoholic solvent in an amount su?icient to substantially
prevent a buildup of para?in deposits on the surfaces of
?owing gas from said well for a period of from 1 hour to
said conduit, said solution further comprising 33—75 parts
7 days to agitate the injected ?uids, and venting said
by weight of quaternary ammonium salts, between 0.5
tubing to the atmosphere, thereby permitting sporadic
and 1.6 parts by weight of sodium chloride, between 10
discharge of chunks of para?in from said tubing by the
and 42 parts by weight of hydrocarbon solvent, and be
fluid energy of said hydrocarbon ?uid which continues
tween 6.5 and 41 parts by weight of water.
until unimpeded flow of said hydrocarbon ?uid is restored,
7. In the transportation of a hydrocarbon ?uid through
and repeating said method of treatment until said un
a conduit wherein said ?uid contains para?in constituents
impeded ?ow is restored.
which tend to deposit and build up on the surfaces of said
3. In the transportation of a hydrocarbon ?uid
conduit in contact with said ?uid, the improvement which
through a conduit wherein said ?uid contains paraf?n
comprises injecting into said ?uid a solution of an alcohol
constituents which tend to deposit and build up on the
soluble quaternary ammonium salts selected from the
surfaces of said conduits in contact with said ?uid, the
group consisting of monoalkyl quaternary ammonium
improvement which comprises injecting into said ?uid a
salts, dialkyl quaternary ammonium salts, and mixed
solution of an alcohol soluble quaternary ammonium salt
selected from the group consisting of monoalkyl quater 25 monoalkyl and dialkyl quaternary ammonium salts, hav
ing from 5 to 20 carbon atoms in each alkyl group in an
nary ammonium salts, dialkyl quaternary ammonium
salts, and mixed monoalkyl and dialkyl quaternary
ammonium salts, having from 5 to 20 carbon atoms in
each alkyl group in an alcoholic solvent in an amount
alcoholic solvent in an amount ranging between one pint
and one gallon per day su?icient to substantially prevent
a build up of para?in deposits on the surfaces of said
conduit, said solution further comprising 33—75 parts by
weight of quaternary ammonium salts, between 0.5 and
1.6 parts by weight of sodium chloride, between 10 and
4-. A method of removing deposits of normally solid
42 parts by Weight of hydrocarbon solvent, and between
para?ins from metal surfaces in contact with a hydro
6.5 and 41 parts by weight of water.
carbon ?uid which comprises the steps of injecting be
8. A method of removing deposits of normally solid
tween 1 and 20 gallons of a solution of quaternary 35
para?ins from metal surfaces in contact with a hydro
ammonium salts selected from the group consisting of
carbon ?uid which comprises charging a solution of
monoalkyl quaternary ammonium salts, dialkyl quater
quaternary ammonium salts selected from the group con
nary ammonium salts, and mixed monoalkyl and dialkyl
sisting of monoalkyl quaternary ammonium salts, dialkyl
quaternary ammonium salts, having from 5 to 50 carbon
atoms in each alkyl group in an alcoholic solvent into 40 quaternary ammonium salts, and mixed monoalkyl and
dialkyl quaternary ammonium salts, having from 5 to 20
a well tubing plugged by paraf?n deposits, following the
sufficient to substantially prevent a build up of para?in
deposits on the surfaces of said conduit.
carbon atoms in each alkyl group in an alcoholic solvent
load in said tubing with a stream of natural gas from
at least about pipeline pressure for a period of 1 to 60
into a well tubing in an amount su?‘icient to remove said
minutes
shutting
pipeline
or" from
which are carried to the ground surface by the ?uid
energy of said hydrocarbon ?uid moving in said well tub
while the annulus is vented to the atmosphere,
the well in until the well pressure exceeds the
pressure, ?owing gas from said well for a period
1 hour to 7 days to agitate the injected ?uids, and
para?ins from the walls of said tubing in large chunks
ing, said solution further comprising 33-75 parts by weight
of quaternary ammonium salts, between 0.5 and 1.6 parts
venting said tubing to the atmosphere, thereby permitting
by weight of sodium chloride, between 10 and 42 parts
sporadic discharge of chunks of para?in from said tub
ing by the ?uid energy of said hydrocarbon ?uid which 50 by weight of hydrocarbon solvent, and between 6.5 and
41 parts by Weight of water, thereby permitting restora
continues until unimpeded ?ow of said hydrocarbon ?uid
is restored.
5. A method of removing deposits of normally solid
parat?ns from metal surfaces in contact with a hydro
carbon ?uid which comprises the steps of injecting be‘
tween 1 and 20 gallons of a solution of quaternary
ammonium salts selected from the group consisting of
monoalkyl quaternary ammonium salts, dialkyl quater
nary ammonium salts, and mixed monoalkyl and dialkyl
quaternary ammonium salts, having from 5 to 20 carbon
atoms in each alkyl group in an alcoholic solvent into a
well tubing plugged by para?in deposits, following the load
in said tubing with a stream of natural gas at at least about
tion of unimpeded ?ow of said hydrocarbon ?uid in said
well tubing.
9. The method according to claim 8 in which said
hydrocarbon solvent is selected from the group consist
ing of methanol, ethanol, l-propanol, 2-propanol, l-bu
tanol, Z-butanol, Z-methyl-l-propanol and 2-methyl-2
propauol.
10. A method of removing deposits of normally solid
parai?ns from metal surfaces in contact with a hydro‘
carbon ?uid which comprises charging a solution of
quaternary ammonium salts selected from the group con
sisting of monoalkyl quaternary ammonium salts, dialkyl
quaternary ammonium salts, and mixed monoalkyl and
pipeline pressure for a period of 1 to 60 minutes while
the annulus is vented to the atmosphere, shutting the well 65 dialkyl quaternary ammonium salts, having from 5 to 20
carbon atoms in each alkyl group in an alcoholic solvent
in until the well pressure exceeds the pipeline pressure,
into a well tubing in an amount ranging between one pint
?owing gas from said well for a period of from 1 hour
and one gallon per day su?icient to remove said paraflins
to 7 days to agitate the injected ?uids, and venting said
from the walls of said tubing in large chunks which are
tubing to the atmosphere, thereby permitting sporadic
discharge of chunks of para?in from said tubing by the 70 carried to the ground surface by the ?uid energy of said
hydrocarbon ?uid moving in said well tubing, said solu
?uid energy of said hydrocarbon ?uid which continues
tion further comprising 33-75 parts by weight of quater
nary ammonium salts, between 0.5 and 1.6 parts by
weight of sodium chloride, between 10 and 42 parts by
peded ?ow is restored.
6. In the transportation of a hydrocarbon fluid through 75 weight of, hydrocarbon solvent, and between 6.5 and 41
until unimpeded flow of said hydrocarbon ?uid is ‘restored,
and repeating said method of treatment until said unim
3,077,929
9
parts by weight of water, thereby permitting restoration
of unimpeded flow of said hydrocarbon ?uid in said well
tubing.
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Blair et a1 ____________ __ Aug. 22, 1944
10
2,356,254
Lehman et a1. ________ __ Aug. 22, 1944
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Resuggan ____________ __ June 3,
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1952
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1960
UNITED STATES PATENT OFFICE
:CERTEFRATE E‘ C0 ECTIN
Patent No, 3,077,929
,
February 19, 1963
Michael JD Fetkovich e1; ale
It is hereby certified that error appears in the above numbered pat~
ent requiring correction and that the said Letters Patent should read as
corrected below.
Column 7,
line 39,
for "'50" read M» 20 we,
Signed and sealed this 1st day of October 1963,,
(SEAL)
Attest:
ERNEST We SWIDER
DAVID L LADD
Attesting Gfficer
Commissioner of Patents
UNITED STATES PATENT OFFICE
‘CERTIFICATE OF CORRECTION
Patent No“ 3,077,929
February ‘19. 1963
Michael JD Fetkovich et alo
It is hereby certified that error appears in the above numbered pat~
ent requiring correction and that the said Letters Patent should read as
corrected below°
Column 7, line 39, for "'50" read —~ 20 e-eo
Signed and sealed this 1st day of October 19630
(SEAL)
Attest:
ERNEST W9 SWIDER
Attesting Officer
DAVID L. LADD
Commissioner of Patents